Add date, year, month, and day columns to the interpolation grids using dates from dat_in. The interp.surface function is used after splitting the interpolation matrix by month to fill missing values. Function is used in wrtds.
fill_grd(grd_in, dat_in, interp = FALSE)interpolation grid to fill, either a single mean grid or an individual quantile grid created within wrtds
tidal or tidalmean object
logical for interpolation